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<meta name="description" content="判断命令是否执行成功if [[ $? -eq 0 ]];then A else b;fi# 或if [ $? -eq 0 ];then  命令正确的分支else  命令失败的分支fi 在脚本中执行其他脚本 fork  ( /directory/script.sh)：  如果shell中包含执行命令，那么子命令并不影响父级的命令，在子命令执行完后再执行父级命令。子级的环境变量不会影响到父级。fork">
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        <h1 id="判断命令是否执行成功"><a href="#判断命令是否执行成功" class="headerlink" title="判断命令是否执行成功"></a>判断命令是否执行成功</h1><figure class="highlight bash"><table><tr><td class="code"><pre><div class="line"><span class="keyword">if</span> [[ $? <span class="_">-eq</span> 0 ]];<span class="keyword">then</span> A <span class="keyword">else</span> b;<span class="keyword">fi</span></div><div class="line"><span class="comment"># 或</span></div><div class="line"><span class="keyword">if</span> [ $? <span class="_">-eq</span> 0 ];<span class="keyword">then</span></div><div class="line">  命令正确的分支</div><div class="line"><span class="keyword">else</span></div><div class="line">  命令失败的分支</div><div class="line"><span class="keyword">fi</span></div></pre></td></tr></table></figure>
<h1 id="在脚本中执行其他脚本"><a href="#在脚本中执行其他脚本" class="headerlink" title="在脚本中执行其他脚本"></a>在脚本中执行其他脚本</h1><ul>
<li><p>fork  ( /directory/script.sh)：</p>
<blockquote>
<p>如果shell中包含执行命令，那么子命令并不影响父级的命令，在子命令执行完后再执行父级命令。子级的环境变量不会影响到父级。<br>fork是最普通的, 就是直接在脚本里面用/directory/script.sh来调用script.sh这个脚本.<br>运行的时候开一个sub-shell执行调用的脚本，sub-shell执行的时候, parent-shell还在。<br>sub-shell执行完毕后返回parent-shell. sub-shell从parent-shell继承环境变量.但是sub-shell中的环境变量不会带回parent-shell</p>
</blockquote>
</li>
<li><p>exec (exec /directory/script.sh)：</p>
<blockquote>
<p>执行子级的命令后，不再执行父级命令。<br>exec与fork不同，不需要新开一个sub-shell来执行被调用的脚本.  被调用的脚本与父脚本在同一个shell内执行。但是使用exec调用一个新脚本以后, 父脚本中exec行之后的内容就不会再执行了。这是exec和source的区别</p>
</blockquote>
</li>
<li><p>source (source /directory/script.sh)：</p>
<blockquote>
<p>执行子级命令后继续执行父级命令，同时子级设置的环境变量会影响到父级的环境变量。<br>与fork的区别是不新开一个sub-shell来执行被调用的脚本，而是在同一个shell中执行. 所以被调用的脚本中声明的变量和环境变量, 都可以在主脚本中得到和使用.</p>
<h1 id="获取时间"><a href="#获取时间" class="headerlink" title="获取时间"></a>获取时间</h1><figure class="highlight plain"><table><tr><td class="code"><pre><div class="line">file_name=&quot;`date +%y%m%d`.sql&quot;</div><div class="line"># 结果：170109.sql</div></pre></td></tr></table></figure>
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</ul>
<h1 id="参数"><a href="#参数" class="headerlink" title="参数"></a>参数</h1><figure class="highlight plain"><table><tr><td class="code"><pre><div class="line"># 将参数赋值给file_name变量，注意=两边不能有空格</div><div class="line">file_name=$1</div></pre></td></tr></table></figure>

      
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              <div class="post-toc-content"><ol class="nav"><li class="nav-item nav-level-1"><a class="nav-link" href="#判断命令是否执行成功"><span class="nav-number">1.</span> <span class="nav-text">判断命令是否执行成功</span></a></li><li class="nav-item nav-level-1"><a class="nav-link" href="#在脚本中执行其他脚本"><span class="nav-number">2.</span> <span class="nav-text">在脚本中执行其他脚本</span></a></li><li class="nav-item nav-level-1"><a class="nav-link" href="#获取时间"><span class="nav-number">3.</span> <span class="nav-text">获取时间</span></a></li><li class="nav-item nav-level-1"><a class="nav-link" href="#参数"><span class="nav-number">4.</span> <span class="nav-text">参数</span></a></li></ol></div>
            

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